DIGESTIVE ORGANS AND THEIR ANATOMY. 289 



not to be confounded with the regular sweetbread of the 

 neck, th,e thymus gland. 



8. THE LIVEE. 



By far the largest gland in the body is the liver. It has 

 the irregular shape familiar to all, as it is displayed at 

 the meat market. The human liver is divided into two 

 main lobes, a larger right lobe and a smaller left lobe, 

 separated more or less by the round ligament of the liver 

 which is the remnant of a blood-vessel of embryonic life. It 

 measures on an average from five to seven inches in its 

 greatest vertical extent, and its greatest transverse diameter 

 is about the same. In bulk the liver occupies about 100 

 cubic inches and weighs from three and one-half to four 

 and one -half pounds. It is thus about -gV to iV of the 

 weight of the whole body. In foetal life it is proportion- 

 ately, however, much heavier, being at birth sometimes as 

 much as iV of the entire bodily weight. It has a character- 

 istic dull reddish brown color. The ease with which it 

 may be cut or torn is readily exemplified on the butcher's 



Fig. 117. CROSS-SECTION OF A PORTAL CANAL. (Capsule of Glisson.) 

 v, portal vein; d, bile-duct; o, hepatic artery; I, lymphatic; 6, blood-vessel in the 

 tissue of the canal itself. 



counter. It is covered over with peritoneum, but has in ad- 

 dition a covering of its own called the capsiile of Glisson. 

 19 



